Air compressor



Y Dec. 30,1930. B. BlscHoF 1,786,595

AIR COMPRESSOR Filed NOV. l2. 1927 2 Sheets-Sheet l De. 30, 1930. n Q BISCHOF 1,786,595

AIR COMPRESSOR Filed Nov. 12. 1927 2 sheets-sheet 2\ Patented Dec.l 30, 1930 BERNHARD BISCHOF, F WINTERTHUR, SWITZERLAND, ASSIGNOR 0F ONE-HAL?? T0 4 CHARLES HACCI'US, 0F COLOGNY-GENEVA, SWITZERLAND .AIR COMPRESSOR Application filed November 12, 1927, Serial No. 232,884, and in Germany November 15, 1926.

ln -rotary air compressors, the pistons, re-

- volving at a distance from the shaft of the compressor, are thrown outward by centrifugal force. The greater the dimensions of the pistons and the more the center of gravity of the pistons is away from the shaft, the more careful the compensation of masses has to be effected, in order to prevent the compressor from vibrating. Compressors with a single piston could not be constructed under the usual mode of constructions, as the vibrations would be too great under high speed.

According to the present-invention, the compressor-cylinder extends crosswise through the axis of rotation of the compressor, so that the piston is moving through this axis. rllhe particles of the mass of the piston run consequently as far as possible close to the axis of rotation and the uncompensated masses have been reduced to a minimum. A perfect compensation of masses must not take place, as the piston has to'be moved by centrifugal force.`

rlhe bore of the cylinder is preferably arrangedin the compressor-shaft. rlhe advantage of a very compact construction is hereby gained. vThe controlling surfaces'of the cylinder have furthermore under a high number of revolutions a small circumferential velocity, whereby good working and long life of the compressor are ensured.

.The revolving shaft containing the cylinder-bore is preferably disposed in a bearing receiving the supplyand discharge-ports or orifices of the Huid. The advantage of this arrangement consists therein, that the crosssections of the supply and discharge-ports can be made sufciently large. ln the known arrangements, in which the cylinders revolve around a stationary shaft receiving the supplyand discharge-ports, the diameters of the ports had to be kept comparatively small in order to prevent the shaft-diameter from becoming too large.

The eccentrically arranged ring, with which the piston abats, is preferably made displaceable into a concentric position; the rlng 1s .however usually retained in its eccentrlc position by a yielding pressure. In

.this construction of the compressor injury to the piston is avoided if liquid enters the sors, used for instance. for householc refrig-` erating-machines.

rlhe subject of the present invention is illustrated in the drawings by way of an example and Fig. 1 is a vertical, central section through a vertical compressor on the line 1-1 of Fig. 3.

Fig. 2 is a horizontal cross-section on the line `2 2 of Fig. 1.

Fig. 3 is a horizontal section on the line 3--3 of Fig. 1.

Fig. i is a vertical, central sect/ion through another construction of a vertical com ressor, on the broken line 4--4 of Fig. 5, an

Fig. 5 is a horizontal section on the line 5-5 of Fig. 4.

ln the construction according to Figs. 1 3, the stator 2 of an electro-motor is arranged in a casing 1, the rotor 4 of which is mounted upon ashaft 3. The said shaft has an enlarged portion 5, in which a cross-bore 6 is provided. In this bore, a piston i is arranged. 'lhe piston-rod 7 of this piston carries a roller 8 abutting on the inner ring 9 of a ball-bearing 9". The central axis of the ball-bearing does not coincide with the central axis of the'compressor-shaft 3.

The piston-rod 7 7. rlihe portion 5 of the shaft 3 is surrounded by a bushing 10 being rotatably arranged in a bearing "16 of the casing 1. This bushing contains the distributing-port or orifice 11 by way of which the fluid can enter the cylinder and be discharged from the said cylinder.

In the bearing'l a port 12 is provided for the supply and a port 13 for the discharge of the fluid. 0n the shaft 3 a ball-bearing 14; is provided, the outer ring of which fits with is heavier than the piston small play into the bearing 16. By means of a spring 15 the bearing 14 and the shaft 3, 5 with the bushing 1() are forced towards the pressure-port 13. By this means a complete joint of the bushing 10 towards the bearing 16 upon the pressure side is obtained.

The Inode of action is as follows: Consequent to the rotation of the compressor-shaft 3 the piston 7 is thrown under a certain angular velocity of the shaft 3 outward, as the piston-rod 7 with the roller 8 are heavier than the piston 7. y

If the piston is freely supported in its cylinder', the roller 8 abuts under influence of the centrifugal force on the inner ring 9 of the ball-bearing 9. The ring 9 might eventu'- ally be arranged rigid in the compressor-casing. Under its outward movement, the piston sucks air through the port 11 in the bushing 10 into the cylinder 6, passing by way of the suction-port 12 to the canal 11. Consequent to the rotation of the shaft 3 the connexion of the cylinder 6 with the suction-port 12 is interrupted, while the piston is moved by the ring 9 inwardly and the air contained in the cylinder 6 compressed. Under further rotation of the compressor-shaft 3 the port 11 will coincide with the pressure-port 13, so that the compressed air can escape through said pressure-port.

If the device is not used as a compressor or pump, but as a driving-motor, the pressure-medium is supplied by way of the port 13, While the expanded pressure-medium escapes through the port 12, the produced energlylbeing taken off the shaft 3.

e compressor may be provided with a plurality of cylinders, which are in this event superposed and the cylinder-axis are staggered towards each other.

The construction according to Figs. 4 and 5 differs from the one according to Figs. 1-3, in thatu the ring 9, on which the roller 8 of the piston-rod 7 abuts, is not rigidly supported, but displactable. The 'ring 9, which is usually disposed eccentrically to the central axis of the compressor can, consequent to this sliding-capacity, move into a concentric, or approximately concentric position to the central axis of the compressor.

Guides 17 are to this end provided in the casing 1, permitting a movement of the ring towards the opposite side of the pressureport 13. The ring 9 is generally retained in eccentric position by the springs 16. These springs are so dimensioned, that they will i yield under excessive pressures, permitting a displacement of the ring. As the ring nears the concentric position, the stroke of the-piston gets less and less until it becomes zero under perfectly concentric position of the ring 9. An inadmissible increase of the pressure can therefore never arise under lack of cooling-water.

In the illustrated example of executing the invention the ring 9 on which the roller 8 abuts, is 'shown as the inner ring of a ball bearing 9', but a stationary ring may likewise be employed.

I claim 1. In an air compressor, in combination, a rotating shaft having a cross bore constituting a working cylinder, a piston reciprocable in said cylinder, an electric motor armature carried by said shaft, a stator casing, a shaft bearing containing radial fluid inlet and discharge ports, a ball bearing arranged on the shaft and including an outer ring tting with small play into the bearing containing the ports, and a pressure device forcing said ring against that side of the bearing containing the discharge ports.

2. In an air compressor, in combination, a rotating shaft having a cross bore constituting a working cylinder, a piston reciprocable therein, an eccentrically arranged ring surrounding the shaft, means on the piston engaging the ring, said ring being displaceable into a substantially concentric position with respect to the shaft, and yieldable pressure means for normally retaining said `ring in its eccentric position.

In an air compressor, in combination, a rotating shaft having a cross bore constituting a working cylinder, a piston reciprocable therein, an eccentrically arranged ring sur rounding the shaft, a piston rod on said piston, its free end engaging the ring, said ring being displaceable into a substantially concentric position with respect to the shaft, and yieldable pressure means for normally ietaining said ring in its eccentric position.

In testimony whereof I have affixed my signature.

BERNHARD BISCHOF. 

